arch/x86/include/asm/fpu/types.h

Source file repositories/reference/linux-study-clean/arch/x86/include/asm/fpu/types.h

File Facts

System
Linux kernel
Corpus path
arch/x86/include/asm/fpu/types.h
Extension
.h
Size
15811 bytes
Lines
648
Domain
Architecture Layer
Bucket
arch/x86
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

struct fregs_state {
	u32			cwd;	/* FPU Control Word		*/
	u32			swd;	/* FPU Status Word		*/
	u32			twd;	/* FPU Tag Word			*/
	u32			fip;	/* FPU IP Offset		*/
	u32			fcs;	/* FPU IP Selector		*/
	u32			foo;	/* FPU Operand Pointer Offset	*/
	u32			fos;	/* FPU Operand Pointer Selector	*/

	/* 8*10 bytes for each FP-reg = 80 bytes:			*/
	u32			st_space[20];

	/* Software status information [not touched by FSAVE]:		*/
	u32			status;
};

/*
 * The legacy fx SSE/MMX FPU state format, as saved by FXSAVE and
 * restored by the FXRSTOR instructions. It's similar to the FSAVE
 * format, but differs in some areas, plus has extensions at
 * the end for the XMM registers.
 */
struct fxregs_state {
	u16			cwd; /* Control Word			*/
	u16			swd; /* Status Word			*/
	u16			twd; /* Tag Word			*/
	u16			fop; /* Last Instruction Opcode		*/
	union {
		struct {
			u64	rip; /* Instruction Pointer		*/
			u64	rdp; /* Data Pointer			*/
		};
		struct {
			u32	fip; /* FPU IP Offset			*/
			u32	fcs; /* FPU IP Selector			*/
			u32	foo; /* FPU Operand Offset		*/
			u32	fos; /* FPU Operand Selector		*/
		};
	};
	u32			mxcsr;		/* MXCSR Register State */
	u32			mxcsr_mask;	/* MXCSR Mask		*/

	/* 8*16 bytes for each FP-reg = 128 bytes:			*/
	u32			st_space[32];

	/* 16*16 bytes for each XMM-reg = 256 bytes:			*/
	u32			xmm_space[64];

	u32			padding[12];

	union {
		u32		padding1[12];
		u32		sw_reserved[12];
	};

} __attribute__((aligned(16)));

/* Default value for fxregs_state.mxcsr: */
#define MXCSR_DEFAULT		0x1f80

/* Copy both mxcsr & mxcsr_flags with a single u64 memcpy: */
#define MXCSR_AND_FLAGS_SIZE sizeof(u64)

/*
 * Software based FPU emulation state. This is arbitrary really,
 * it matches the x87 format to make it easier to understand:
 */
struct swregs_state {
	u32			cwd;
	u32			swd;
	u32			twd;
	u32			fip;
	u32			fcs;
	u32			foo;
	u32			fos;
	/* 8*10 bytes for each FP-reg = 80 bytes: */
	u32			st_space[20];
	u8			ftop;
	u8			changed;
	u8			lookahead;
	u8			no_update;
	u8			rm;
	u8			alimit;
	struct math_emu_info	*info;
	u32			entry_eip;
};

/*
 * List of XSAVE features Linux knows about:
 */

Annotation

Implementation Notes